1 US Gallon = 231 Cubic Inches So if you find out the cubic inches you can convert it to gallons. Example: If your tank is 3 ft wide by 2 ft deep and 2 ft high.
36 inches x 24 inches x 24 inches = 20736 cubic inches / 231 per gallon = 90 gallons
This size tank can hold up to 7,779.74 US gallons of water.
== 478.79 gallons, there are 7.481 gallons in a square foot. So that is 64 x 7.481== 478.79.==http://dictionary.reference.com/writing/styleguide/weights.html
Multiply the number of cubic feet in the tank by 7.5 to find gallons.
209.52 gallons. Lx Wx H /231 = GALLONS
A 20 Gallon tank can hold up to 20 gallons of water.
2000 gallons
10 ft X 10 ft square tank will hold 1000 cubic feet of water or 7480.51 gallons 10 ft round tank will hold 785 cubic feet of water or 5872.207 gallons
886,174
This tank will hold a maximum of 10,030 gallons of water.
About 157.1 gallons.
A 15 cubic foot tank will hold a maximum of about 112.2 gallons of water.
A 1,000 cubic foot tank holds up to 7,480 US gallons of water.